All ethnic groups in the People's Republic of China are equal. The state protects the lawful rights and interests of the minority ethnic groups and upholds and develops a relationship of equality, unity and mutual assistance among all of China's ethnic groups. Discrimination against and oppression of any ethnic group are prohibited; any act that undermines the unity of the ethnic groups or instigates division is prohibited.

The state assists areas inhabited by minority ethnic groups in accelerating their economic and cultural development according to the characteristics and needs of the various minority ethnic groups.

Regional autonomy is practiced in areas where people of minority ethnic groups live in compact communities; in these areas organs of self-government are established to exercise the power of autonomy. All ethnic autonomous areas are integral parts of the People's Republic of China.

All ethnic groups have the freedom to use and develop their own spoken and written languages and to preserve or reform their own folkways and customs.

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Article 36

Citizens of the People's Republic of China enjoy freedom of religious belief.

No state organ, public organization or individual may compel citizens to believe in, or not to believe in, any religion; nor may they discriminate against citizens who believe in, or do not believe in, any religion.

The state protects normal religious activities. No one may make use of religion to engage in activities that disrupt public order, impair the health of citizens or interfere with the educational system of the state.

Religious bodies and religious affairs are not subject to any foreign domination.

Source: China Yearbook 2004

As quoted above, human rights of minorities and freedom of religions are protected by the Constitution in China.
Additionally, in 1984, the Law of Autonomous Areas was established to guarantee equality of every minority, minorities' culture and languages, freedom of using and developing their languages, protection of their manners and customs, their autonomy, etc.
In November 2004, new Ordinance of Religions was established in the form of administrating religious activities.
In addition to those domestic constitution and laws in China, respect for human rights and equality of all races are advocated in Charter of the United Nations, which China is one of the permanent member, and in International Covenant on Civil and Political Rights, International Convention on All Form of Racial Discrimination, etc, which China has contracted.

However, China acts the whole against their own creditable "lemma" or international conventions.
One of them, the suppression of religions, is described in this chapter.

Tibetan Buddhism has been pressured to refuse Dalai Lama and to have patriotic spirit for China. More than 180 monks and nuns have been imprisoned and arbitrary detention and judicial trials have been going on. Many cases of torture and abusive treatment have also been reported. The youngest political prisoner Panchen Lama XI was taken away by Chinese government right after his appointment at the age of 6, and since then, nobody knows where he has disappeared.

Chinese government has ignored Vatican completely and appointed Catholic priests of China, by China, and for China. It has been said that more than 40 unregistered priests who are not authorized by Chinese government are being imprisoned even now. Besides, Chinese government has been postulating that Vatican must give up to appoint priests in China and break off its relation with Taiwan before starting conversation with Vatican.

Restriction on Islam is even stronger compared to that on the others; especially against Uyghur. Every mosque must be registered at the Islamic Association of China. Muslim clerics above Imam must be authorized by Chinese government and must take patriotic training routinely.

Repression on unregistered Protestant groups also has been continued. Hundreds of people who didn't have permission by Chinese government and had their meetings at their own houses have been arrested.

Suppression on the Falun Gong, which was banned as a "heretical organization" in July 1999, has been powered up. Tens of thousands of disciplinants are being in prisons and would be abused as far as giving up their belief. It's said that there has been over 1000 victims since becoming "heretical organization".

China has established laws and social systems in principle. However, political measures are more important than laws for them, laws don't work at all in practice. And, people in government and police are lack of law-abiding sense so that these laws are run very arbitrarily. Their "freedom of religion" is guaranteed or controlled just by the government's caprice.

Nowadays, some religious activities are strictly forbidden at school in East Turkistan: to celebrate religious holidays: to study on religious textbooks: to wear religious costumes: and so forth. Children under 18 years old are prohibited to enter mosques and to take any religious education at home. Furthermore, Chinese government strictly controls everything such as who becomes cleric, which version of al-Quran (a.k.a. The Koran) can be used, what must be or must not be in religious speech for public event, etc.
The Cultural Revolution was the worst time-period for religions; a number of mosques were enforced to close off and lots of cletics got imprisoned. After the Cultural Revolution, things had gradually become a bit better, but since the mid-90's, a nightmare has come back again. Hundreds of mosques have been shut off, Muslim clerics above Imam must be authorized by Chinese government, and they are required to take a patriot training every year to renew their authorization.
If somebody offends against those rules, he/she will be kicked out of jobs, faced financial penalty, registered in the black list, got their family harassed, detained, sent to a forced labor camp, and so on.
We can conclude that the purpose of Chinese government is to make it uneasy to have any religious activities without their permission and, even if they permit, to keep religious groups under their control.

Since the mid-90's, when the Soviet Union broke down and some countries succeeded to be independent in Central Asia, suppression on Islam has become stronger. The "Strike Hard" campaign, which is applied to usual crimes in China, is being used for religious suppression in East Turkistan. Their logic is that Uyghur religious activities are conducted by separationist, therefore they must be punished severely.
Control on Uyghur religious activities are even stronger than on the others. The reason is, probably, the other races already have their own independent countries such as Kazakhstan, Tajikistan, Uzbekistan, and Mongolia, so they hardly intend to drive for national independence.
Islam plays a very important role to build an identity for Turk people. This means that crack down on their religion by Chinese government is not only religious suppression but also a fear to deny their ethnic identity.